Correct formatting in include/openmc/particle.h
Correct formatting in include/openmc/particle.h

Co-Authored-By: Simon Richards <18cb310aa2938afb3dd6e3bf973fc34b2a5a080b@physics.org>
amandalund/openmc,liangjg/openmc,liangjg/openmc,mit-crpg/openmc,walshjon/openmc,shikhar413/openmc,amandalund/openmc,paulromano/openmc,paulromano/openmc,walshjon/openmc,paulromano/openmc,smharper/openmc,shikhar413/openmc,mit-crpg/openmc,liangjg/openmc,smharper/openmc,paulromano/openmc,mit-crpg/openmc,walshjon/openmc,smharper/openmc,liangjg/openmc,mit-crpg/openmc,shikhar413/openmc,walshjon/openmc,amandalund/openmc,smharper/openmc,shikhar413/openmc,amandalund/openmc